     nil))
 
 (defn audio-title-options
+  "Returns the encoding options for adding a title to an audio track."
   [index codec lang chans]
   [(str "-metadata:s:a:" index) (str "title=" (audio-title codec lang chans))])
 

      (json/read-str (:out exec) :key-fn keyword))))

(defn detect-interlace
  [input]
  (let [output (:err (exec "ffmpeg" "-y" "-ss" 300 "-i" input "-f" "matroska"
                           "-t" 120 "-an" "-sn" "-vf" "idet" "/dev/null"))]

   (audio-options spec)
   (subtitle-options spec)
   "-f" (ffmpeg-format (:format spec))
   (format-options spec)
   "-threads" 0
   (:output spec)])

